Department of Bioengineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Science. 2014 Feb 21;343(6173):873-5. doi: 10.1126/science.1247811.
Hydrogels are three-dimensional polymer networks that contain a large amount of water inside. Certain hydrogels can be injected in solution and transformed into the gel state with the required shape. Despite their potential biomedical applications, the use of hydrogels has been severely limited because all the conventional hydrogels inevitably "swell" under physiological conditions, which drastically degrades their mechanical properties. We report the synthesis of injectable "nonswellable" hydrogels from hydrophilic and thermoresponsive polymers, in which two independently occurring effects (swelling and shrinking) oppose each other. The hydrogels can endure a compressive stress up to 60 megapascals and can be stretched more than sevenfold without hysteresis. Our results demonstrate that the suppression of swelling helps retain the mechanical properties of hydrogels under physiological conditions.
水凝胶是三维聚合物网络，内部含有大量水分。某些水凝胶可以在溶液中注射，并转变为具有所需形状的凝胶状态。尽管水凝胶具有潜在的生物医学应用，但由于所有传统水凝胶在生理条件下不可避免地“溶胀”，这极大地降低了它们的机械性能，因此其应用受到严重限制。我们报告了由亲水性和温敏性聚合物合成的可注射的“不可溶胀”水凝胶，其中两个独立发生的效应（溶胀和收缩）相互对抗。水凝胶可以承受高达 60 兆帕斯卡的压缩应力，并且可以在没有滞后的情况下拉伸超过七倍。我们的结果表明，抑制溶胀有助于在生理条件下保持水凝胶的机械性能。
